1. Field of the Invention
The invention relates to a conductor for transmitting electrical power.
It relates more precisely to a conductor comprising a cylindrical core clad with a strip of metallic material, possibly comprising a superconductor, placed, in the shape of a tube, longitudinally around said core, its longitudinal edges being welded to each other along a weld seam.
2. Description of Related Art
For this type of conductor, the strip may consist of                a conventional conductor, for example copper on an aluminum core;        a nickel, nickel-alloy or steel substrate intended for deposition, after welding, of one or more ceramic lavers comprising at least one superconductor layer;        a metal substrate already coated with one or more nonsuperconducting ceramic layers intended for deposition, after welding of at least one superconductor laver; or        a metal substrate already coated with a plurality of ceramic layers at least one of which is a superconductor layer.        
For example, patent GB 1 275 985 describes such a conductor, comprising a cylindrical core coated with a strip comprising superconductors placed, in the shape of a tube, longitudinally around said core, its longitudinal edges being welded to each other along a weld seam.
This type of conductor is manufactured using a draw-down operation.
The strip of metallic material, possibly comprising a superconductor, is placed longitudinally about the core, its longitudinal edges being welded to each other along a weld seam preferably produced by laser welding or by gas-shielded arc welding, i.e. TIG (tungsten inert gas) welding, then drawn down around the core. This tube is drawn down over the core with an area reduction ranging between 10 and 15%. The strip is then pressed against the core.
Manufacture using draw-down after welding is necessary at the present time because, to carry out the welding, it is indispensible to have an empty space under the weld seam. This welding of the tube formed by the strip is therefore carried out on a diameter larger than the diameter of the final product, and then this tube is drawn down so as to he pressed against the cylindrical core,